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   <title>Zoltan User's Guide:  Geometric (Coordinate-Based) Partitioners</title>
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<div align=right><b><i><a href="ug.html">Zoltan User's Guide</a>&nbsp;
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<h2>
<a name="GEOM"></a>Geometric (Coordinate-based) Partitioners</h2>

Geometric partitioners divide data into parts based on the physical
coordinates of the data.  Objects assigned to a single part tend to be
physically close to each other in space.  Such partitioners are very useful for
applications that don't have explicit 
connectivity information (such as particle methods) or for which geometric
locality is important (such as contact detection).  
They are also widely used in adaptive finite
element methods because, in general, they execute very quickly and yield
moderately good partition quality.

<p>
The geometric methods are the easiest non-trivial partitioners to incorporate
into applications, as they require only four callbacks:  two returning
<a href="ug_query_lb.html#General Functions">object information</a> and 
two returning <a href="ug_query_lb.html#Geometry-based Functions">coordinate 
information</a>.

<p>
We group <a href="ug_alg_reftree.html">refinement-tree partitioning</a>
for adaptive mesh refinement applications
into the geometric partitioners because
it uses geometric information to determine an initial ordering for coarse
elements of adaptively refined meshes.  The refinement-tree partitioner
also requires <a href="ug_query_lb.html#Tree-based Functions">tree-based 
callbacks</a> with connectivity information between
coarse and fine elements in refined meshes.

<blockquote>
<a href="ug_alg_rcb.html">Recursive Coordinate Bisection</a> (RCB)
<br><a href="ug_alg_rib.html">Recursive Inertial Bisection</a> (RIB)
<br><a href="ug_alg_hsfc.html">Hilbert Space-Filling Curve Partitioning</a> (HSFC)
<br><a href="ug_alg_reftree.html">Refinement Tree Based Partitioning</a> (Reftree)
</blockquote>



<p>
<hr WIDTH="100%">[<a href="ug.html">Table of Contents</a>&nbsp; | <a href="ug_alg_rcb.html">Next:&nbsp;
Recursive Coordinate Bisection</a>&nbsp; |&nbsp; <a href="ug_alg_random.html">Previous:&nbsp;
Random Partitioning</a>&nbsp; |&nbsp; <a href="https://www.sandia.gov/general/privacy-security/index.html">Privacy and Security</a>]
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